Hadith 4:240

Narrated Jabir bin 'Abdullah:

On the day of the battle of the Trench, the Prophet wanted somebody
from amongst the people to volunteer to be a reconnoitre. Az-Zubair
volunteered. He demanded the same again and Az-Zubair volunteered
again. Then he repeated the same demand (thrice) and AzZubair
volunteered once more. The Prophet then said, " Every prophet has a
disciple and my disciple is Az-Zubair."